Decomposition of Potassium Ferrate(VI)(K2FeO4) and Potassium Ferrate(III)(KFeO2): In-situ Moessbauer Spectroscopy Approach

Moessbauer spectroscopy was shown to be very useful technique studying the mechanism of thermal decomposition or aging processes of the most known ferrate(VI), K2FeO4. In-situ Moessbauer spectroscopy approach was used to monitor the phase composition during the studied processes. The experimental set-up was designed to perform in-situ measurements at high temperatures and at different air humid conditions at room temperature. The potassium ferrate(III), KFeO2 was demonstrated to be the primary product of thermal decomposition of K2FeO4. The KFeO2 was unstable in a humid air at room temperature and reacted with components of air, H2O and CO2 to give Fe2O3 nanoparticles and KHCO3. The aging kinetics of K2FeO4 and KFeO2 under humid air were significantly dependent on the relative air humidity.